LOS ANGELES — Emma and Jens Grede are best known as the couple running some of the most successful American fashion brands to launch in the past decade — many of which are co-piloted by members of the Kardashian-Jenner family. But when it comes down to it, they’re just two branding nerds who love talking shop.
“When people do something so obvious, [like] when Rihanna did Fenty [beauty] — ” Jens starts in his Swedish-flecked accent,…